原煤可磨性对气流床粉煤气化混配煤煤粉均匀程度的影响
Effect of raw coal grindability on the uniformity of pulverized blended coal for entrained-flow pulverized coal gasification
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摘要: 以气流床粉煤气化工业装置不同时期的两组进料煤粉为研究对象, 在实验室按粒径对两组煤粉进行了筛分分组, 对分组后子煤粉进行了煤质、煤灰特性及反应活性分析, 研究了原煤可磨性差异对混配磨制后煤粉均匀程度的影响.结果表明, 原煤可磨性对混煤煤粉的颗粒粒径分布及其均匀性均具有影响.混配磨制煤粉的粒径主要取决于原煤中可磨性指数较小的原煤, 此原煤可磨性指数越小, 煤粉颗粒粒径越大; 可磨性相近的原煤混配制得的煤粉混合较均匀, 可磨性差异较大的原煤混配煤粉混合不均, 煤粉发生偏析, 使得大颗粒煤粉中含有过多的难磨煤, 导致煤粉的反应性能变差.Abstract: Two pulverized coals taken from an entrained-flow pulverized coal gasification unit at different operating periods were adopted as the experimental materials, which were divided into two groups based on the partical size to investigate the effect of raw coal grindability on the uniformity of pulverized blended coal. The coal quality and the ash character of the subsamples were analyzed as well. The results show that the grindability of raw coal has a great influence on the partical size distribution and the uniformity of pulverized blended coal, and the partical size distribution of blended coal is mainly depended on the raw coal with a smaller grindability index. The smaller the raw coal's grindability index, the larger the particle size of the pulverized blended coal. It is therefore concluded that the pulverized blended coal made from similar grindability raw coals is more uniform. On the other hand, different grindabilities of raw coals lead to nonuniformity and segregation of the pulverized blended coal and induce an accumulation of hard coal in the large particles, which will cause the reactivity of the pulverized blended coal decrease.